0917Androird基础自定义View(Matrix)

　关于Matrix的详细资料http://www.cnblogs.com/qiengo/archive/2012/06/30/2570874.html#symmetrical

Matrix

　　本文只介绍了Martrix的一些具体用法，原理方面的请参考上面的链接。
　　新建一个类继承View，继承他的俩构造器和onDraw以及onMeasure方法。在构造器中初始化Bitmap以及Matrix

//        初始化bitmap对象
        mBitmap= BitmapFactory.decodeResource(getResources(), R.mipmap.text);
        mPaint=new Paint();
        matrix=new Matrix();
        mBitmapHeight=mBitmap.getHeight();
        mBitmapWidth=mBitmap.getWidth();

        mPaint.setColor(Color.BLACK);
        mPaint.setAntiAlias(true);
        mPaint.setStrokeWidth(10);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setTextSize(30);

　　在onDraw中设置图形的位置，不细说，用的时候查API

    matrix.reset();
        matrix.postScale(4, 4.0f);//放大缩小（float x,float y）
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();//重置
        canvas.drawBitmap(mBitmap, matrix, mPaint);//原图

        matrix.reset();
        matrix.postTranslate(mBitmapWidth, mBitmapHeight);//平移（float x,float y）
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        matrix.postRotate(180);//旋转180度，默认旋转中心是左上角的点
        //默认的中心点旋转180后出去了。。。所以需要平移回来
        matrix.postTranslate(mBitmapWidth, mBitmapHeight * 3);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        matrix.postSkew(0, 2);//错切，面积不变（float x,float y）
        matrix.postTranslate(mBitmapWidth*2,0);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        float matrix_values[]={1f,0f, 0f, 0f, -1f, 0f,0f,0f,1f};//关于x轴对称，倒影效果
        matrix.setValues(matrix_values);
        matrix.postTranslate(0,mBitmapHeight*2);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        float matrix_values2[]={-1f,0f,0f,0f,1f,0f,0f,0f,1f};//关于y轴对称
        matrix.setValues(matrix_values2);
        matrix.postTranslate(mBitmapWidth*2,0);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

　　附一张效果图
　　

　　全部代码（记得将自定义View添加到布局中）

package com.example.laowang.android0916canvas_.weight;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;

import com.example.laowang.android0916canvas_.R;

/**
 * Created by Administrator on 2015/9/17.
 */
public class MyBitmapView extends View {
    private int mWith;
    private int mHeight;
    private int mBitmapHeight;
    private int mBitmapWidth;
    private Paint mPaint;
    private Bitmap mBitmap;
    private Matrix matrix;

    public MyBitmapView(Context context) {
        super(context);
    }

    public MyBitmapView(Context context, AttributeSet attrs) {
        super(context, attrs);
//        初始化bitmap对象
        mBitmap= BitmapFactory.decodeResource(getResources(), R.mipmap.text);
        mPaint=new Paint();
        matrix=new Matrix();
        mBitmapHeight=mBitmap.getHeight();
        mBitmapWidth=mBitmap.getWidth();

        mPaint.setColor(Color.BLACK);
        mPaint.setAntiAlias(true);
        mPaint.setStrokeWidth(10);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setTextSize(30);

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mWith = getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        mHeight = getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);
        setMeasuredDimension(mWith,mHeight);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        matrix.reset();
        matrix.postScale(4, 4.0f);//放大缩小（float x,float y）
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();//重置
        canvas.drawBitmap(mBitmap, matrix, mPaint);//原图

        matrix.reset();
        matrix.postTranslate(mBitmapWidth, mBitmapHeight);//平移（float x,float y）
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        matrix.postRotate(180);//旋转180度，默认旋转中心是左上角的点
        //默认的中心点旋转180后出去了。。。所以需要平移回来
        matrix.postTranslate(mBitmapWidth, mBitmapHeight * 3);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        matrix.postSkew(0, 2);//错切，面积不变（float x,float y）
        matrix.postTranslate(mBitmapWidth*2,0);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        float matrix_values[]={1f,0f, 0f, 0f, -1f, 0f,0f,0f,1f};//关于x轴对称，倒影效果
        matrix.setValues(matrix_values);
        matrix.postTranslate(0,mBitmapHeight*2);
        canvas.drawBitmap(mBitmap, matrix, mPaint);

        matrix.reset();
        float matrix_values2[]={-1f,0f,0f,0f,1f,0f,0f,0f,1f};//关于y轴对称
        matrix.setValues(matrix_values2);
        matrix.postTranslate(mBitmapWidth*2,0);
        canvas.drawBitmap(mBitmap, matrix, mPaint);
    }
}